These patterns and best practices are often bound to a specific platform/language, so they are the first place to look for them.

- [Exception patterns wiki][5] is a general patterns resource.

As an example check the following links for java:

- [Best Practices for Exception Handling][1]
- [15 Best practices about exception handling][2]
- [Exception-Handling Antipatterns][6]

Going through such materials would give you a general idea to follow in exception handling mechanisms.

Also check other SO questions: 

- https://stackoverflow.com/questions/4589750/exception-handling-pattern
- https://stackoverflow.com/questions/425281/java-style-properly-handling-exceptions?rq=1


[1]:http://www.onjava.com/pub/a/onjava/2003/11/19/exceptions.html
[2]:http://codebuild.blogspot.com/2012/01/15-best-practices-about-exception.html
[5]:http://c2.com/cgi/wiki?ExceptionPatterns
[6]:https://community.oracle.com/docs/DOC-983543

Best approach is never to swallow any exceptions within your application code.  Hookup a handler to unhandled exceptions in your applications when bootstrapping where you can show an error message and do some logging.

Some decent books i&#39;ve read recommended this approach.

http://thibautvs.com/blog/?p=2238 is a good one where it&#39;s mentioned.

Description of using exceptions on .NET (but not only) in details: 
[http://msdn.microsoft.com/en-gb/library/5b2yeyab(v=vs.100).aspx][1]

When one should use them, how to write them, how to handle them correctly and so forth...

  [1]: http://msdn.microsoft.com/en-gb/library/5b2yeyab%28v=vs.100%29.aspx

When I try to export my database through MySQL Workbench remotely from localserver,

I am getting some below version error:

&gt;mysqldump Version Mismatch  [Content] mysqldump.exe is version 5.5.16, but the MySQL Server to be dumped has version 5.6.10-log. Because the version of mysqldump is older than the server, some features may not be backed up properly. It is recommended you upgrade your local MySQL client programs, including mysqldump to a version equal to or newer than that of the target server. The path to the dump tool must then be set in Preferences -&gt; Administrator -&gt; Path to mysqldump Tool

I am trying to find a solution - I searched for solution on google but couldn&#39;t find a good answer to solve the issue.

Does anyone know, how to fix this issue in MySQL Workbench?

mysqlworkbench giving version error on exporting database

I&#39;m using `ASP.NET MVC 4`. I am trying to pass data from one controller to another controller.  I&#39;m not getting this right.  I&#39;m not sure if this is possible?

Here is my source action method where I want to pass the data from:

    public class ServerController : Controller
    {
         [HttpPost]
         public ActionResult ApplicationPoolsUpdate(ServiceViewModel viewModel)
         {
              XDocument updatedResultsDocument = myService.UpdateApplicationPools();
    
              // Redirect to ApplicationPool controller and pass
              // updatedResultsDocument to be used in UpdateConfirmation action method
         }
    }

I need to pass it to this action method in this controller:

    public class ApplicationPoolController : Controller
    {
         public ActionResult UpdateConfirmation(XDocument xDocument)
         {
              // Will add implementation code
    
              return View();
         }
    }

I have tried the following in the `ApplicationPoolsUpdate` action method but it doesn&#39;t work:

    return RedirectToAction(&quot;UpdateConfirmation&quot;, &quot;ApplicationPool&quot;, new { xDocument = updatedResultsDocument });
    
    return RedirectToAction(&quot;UpdateConfirmation&quot;, new { controller = &quot;ApplicationPool&quot;, xDocument = updatedResultsDocument });

How would I achieve this?

Passing data between different controller action methods

Is there any resource (web or book) describing exception handling / error handling design patterns?

There is a lot of literature on how to write clean code, and there are a lot of books covering design patterns. I have, however, never seen any design pattern covering the issue of where and how best to handle errors and how best to propagate an error appearing in a low-level function up the levels of abstraction.

Design patterns: exception / error handling

<p>Is there any resource (web or book) describing exception handling / error handling design patterns?</p>
<p>There is a lot of literature on how to write clean code, and there are a lot of books covering design patterns. I have, however, never seen any design pattern covering the issue of where and how best to handle errors and how best to propagate an error appearing in a low-level function up the levels of abstraction.</p>


What is the difference between the **[Observer Pattern][1]**, **[Publish/Subscribe][2]**, and **[Data Binding][3]**?

I searched around a bit on Stack Overflow and did not find any good answers.

What I have come to believe is that data binding is a generic term and there are different ways of implementing it such as the Observer Pattern or the Pub/Sub pattern. With the Observer pattern, an Observable updates its Observers.  With Pub/Sub, 0-many publishers can publish messages of certain classes and 0-many subscribers can subscribe to messages of certain classes.

**Are there other patterns of implementing &quot;data binding&quot;?**

  [1]: http://en.wikipedia.org/wiki/Observer_pattern
  [2]: http://en.wikipedia.org/wiki/Publish%E2%80%93subscribe_pattern
  [3]: http://en.wikipedia.org/wiki/UI_data_binding

Difference between Observer, Pub/Sub, and Data Binding

I need to check a `DateTime` value if it has a value or not.

I have several options:

    if (dateTime == default(DateTime))
or

    if (dateTime == DateTime.MinValue)
or using a nullable `DateTime?`

    if (nullableDateTime.HasValue)

Personally I would prefer the third version, since its pretty good readable.
But in our database we have some datetime columns which are defined as not null.
So in some cases I have to go with the first two options.

I read somewhere that the `default` keyword should be used when working with generics, but isn&#39;t it much more readable in this case? When using the second option I have to know that the default value of a new and empty DateTime instance is DateTime.MinValue which has the smell of an implementation detail for me.

So which option should I use to use &quot;best practice&quot;?


How to check for default DateTime value?

After doing a few Projects using the MVVM Pattern, Im still struggling with the Role of the ViewModel:

What I did in the past:
Using the Model only as a Data Container.
Putting the Logic to manipulate the Data in the ViewModel. (Thats the Business Logic right?)
Con: Logic is not reusable.

What I&#39;m trying now:
Keeping the ViewModel as thin as possible.
Moving all Logic into the Model Layer.
Only keeping presentation Logic in the ViewModel.
Con: Makes UI Notification realy painful If Data is Changed inside the Model Layer.


So I will  give you an Example to make it more clearer:

Scenario:
Tool to Rename Files. 
Classes:
File : Representing each File;
Rule: Contains Logic how to Rename a File;

If Im following approach 1:
Creating a ViewModel for File, Rule and the View -&gt; RenamerViewModel.
Putting all Logic in the RenamerViewModel: 
Containing a List of FileViewModel and RuleViewModel and the proceeding Logic.
Easy and fast, but not reusable.

If Im following approach 2:
Creating a new Model Class -&gt; Renamer, which contains a List of File, Rule und the proceeding Logic to interate over each File and apply each Rule.
Creating a Viewmodel for File, Rule and Renamer.
Now the RenamerViewModel only contains an instance of Renamer Model, plus two ObservableCollections to wrap the File und Rule List of the Renamer.
But the whole Logic is in the Renamer Model. So if the Renamer Model is triggered to manipulate some Data by Method Calls, the ViewModel has no Clue which Data is manipulated.
Because the Model doesnt Contain any PropertyChange Notification and I will avoid that.
So the Business and Presentation Logic is seperated, but this makes it hard to notify the UI.





MVVM: ViewModel and Business Logic Connection

## The Problem

This answer has been answered before but are old and not up to date. I have over 2000 lines of code in a single file, and as we all know this is bad practice, especially when i&#39;m looking through code or adding new features. I want to better organize my code, for now and for the future. 

I should mention that I&#39;m building a tool (not a simple website) with lots of buttons, UI elements, drag, drops, action listeners/handlers and function in the global scope where several listeners may use the same function.

### Example code

    $(&#39;#button1&#39;).on(&#39;click&#39;, function(e){
        // Determined action.
        update_html();
    });

    ... // Around 75 more of this

    function update_html(){ .... }

    ...

[More example code](http://pastebin.com/PrbwanNZ) 

### Conclusion

I really need to organize this code for best use and not to repeat myself and be able to add new features and update old ones. I will be working on this by myself. Some selectors can be 100 lines of code others are 1. I have looked a bit at `require.js` and found it kinda repetitive, and actually writing more code than needed . I&#39;m open to any possible solution that fit this criteria and link to resource / examples are always a plus.

Thanks.

Best way to organize jQuery/JavaScript code (2013)

I have a class called `Writer` that has a function `writeVector` like so:

    void Drawer::writeVector(vector&lt;T&gt; vec, bool index=true)
    {
        for (unsigned int i = 0; i &lt; vec.size(); i++) {
            if (index) {
                cout &lt;&lt; i &lt;&lt; &quot;\t&quot;;
            }
            cout &lt;&lt; vec[i] &lt;&lt; &quot;\n&quot;;
        }
    }

I&#39;m trying not to have a duplicate code, while still worrying about the performance.
In the function, I&#39;m doing the `if (index)` check on every round of my `for`-loop, even though the result is always the same.
This is against &quot;worrying about the performance&quot;.

I could easily avoid this by placing the check outside of my `for`-loop.
However, I&#39;ll get loads of duplicate code:

    void Drawer::writeVector(...)
    {
        if (index) {
            for (...) {
                cout &lt;&lt; i &lt;&lt; &quot;\t&quot; &lt;&lt; vec[i] &lt;&lt; &quot;\n&quot;;
            }
        }
        else {
            for (...) {
                cout &lt;&lt; vec[i] &lt;&lt; &quot;\n&quot;;
            }
        }
    }

So these are both &quot;bad&quot; solutions for me.
What I&#39;ve been thinking, is two private functions, one of them outs the index and then calls the other.
The other one only outs the value.
However, I can&#39;t figure out how to use it with my program, I&#39;d still need the `if` check to see which one to call...

According to the problem, polymorphism seems like a correct solution.
But I can&#39;t see how should I use it here.
What would be the preferred way to solve this kind of problem?

This is not a real program, **I&#39;m just interested in learning how this kind of problem should be solved.**

Avoiding if statement inside a for loop?

Please correct me if this is wrong:  In Java 7&#39;s try-with-resources statement, any exceptions thrown by the resource&#39;s `close()` method must be either declared as thrown by my method or I must wrap the whole try in another `try` which catches any exceptions thrown by `close()`.

If so, I have to wonder if I will make much use of it.  I certainly don&#39;t want to `throw` the exceptions thrown by `close()`, the caller won&#39;t know what to do with that.  And a `try` wrapping another `try` just to handle `close()` would not look very elegant, to me at least.

&lt;b&gt;EDIT:&lt;/b&gt;  I think I accidentally asked two questions, one of which was a duplicate.

Question 1.  Do I have to declare that my method throws the exception from the `close()` method or wrap the try-with-resources in another try?  (Not answered in proposed duplicate.)

Question 2.  Is there a way to close the resource silently?  (Clearly a duplicate, so I am taking that sentence out of the question.  Hopefully this makes the question satisfactorily unique.)

Try-with-resources: Must I throw or catch the close() method&#39;s exceptions?

I can&#39;t seem to find much information about custom exception classes.

**What I do know**

You can declare your custom error class and let it inherit from `StandardError`, so it can be `rescue`d:

    class MyCustomError &lt; StandardError
    end

This allows you to raise it using:

    raise MyCustomError, &quot;A message&quot;

and later, get that message when rescuing

    rescue MyCustomError =&gt; e
      puts e.message # =&gt; &quot;A message&quot;

**What I don&#39;t know**

I want to give my exception some custom fields, but I want to inherit the `message` attribute from the parent class. I found out reading [on this topic](http://www.ruby-forum.com/topic/207448) that `@message` is not an instance variable of the exception class, so I&#39;m worried that my inheritance won&#39;t work.

Can anyone give me more details to this? How would I implement a custom error class with an `object` attribute? Is the following correct:

    class MyCustomError &lt; StandardError
      attr_reader :object
      def initialize(message, object)
        super(message)
        @object = object
      end
    end

And then:

    raise MyCustomError.new(anObject), &quot;A message&quot;

to get:

    rescue MyCustomError =&gt; e
      puts e.message # =&gt; &quot;A message&quot;
      puts e.object # =&gt; anObject

will it work, and if it does, is this the correct way of doing things?

Ruby custom error classes: inheritance of the message attribute

From time to time in Python, I see the block:

    try:
       try_this(whatever)
    except SomeException as exception:
       #Handle exception
    else:
       return something

**What is the reason for the try-except-else to exist?**

I do not like that kind of programming, as it is using exceptions to perform flow control. However, if it is included in the language, there must be a good reason for it, isn&#39;t it?

**It is my understanding that exceptions are not errors**, and that they should only be used for exceptional conditions (e.g. I try to write a file into disk and there is no more space, or maybe I do not have permission), and not for flow control. 

Normally I handle exceptions as:

    something = some_default_value
    try:
        something = try_this(whatever)
    except SomeException as exception:
        #Handle exception
    finally:
        return something

Or if I really do not want to return anything if an exception happens, then:

    try:
        something = try_this(whatever)
        return something
    except SomeException as exception:
        #Handle exception


Is it a good practice to use try-except-else in Python?

I&#39;m using mockito in a junit test. How do you make an exception happen and then assert that it has (generic pseudo-code)

Mockito How to mock and assert a thrown exception?

For some reason this code gives me an uncaught exception error. It seems the catch block is not catching the error. Are try catch blocks scoped in such a way that I cannot throw an error in a nested function, and then expect it to be caught by a catch statement scoped higher up the chain? Some of the sensitive data with in the application that i&#39;m working in has been removed, but it expected that leadInfo[ 0 / 1] would be a 32 character alpha numeric string that I pull from URL parameters.

The underlying issue here is with my AJAX call returning an error from the API and that error not being handled properly within the application. Hence the need for the throw statement. The AJAX call completes fine, and returns a JSON object that does not contain the email address as a property, so I need to handle that in a way that changes the page to reflect that.

        jQuery(document).ready(function(){
    		try {
    			url = &quot;http://api.com/api/v1/lead/&quot; + leadInfo[1]
    			
    			jQuery.ajax({
    			    type: &#39;GET&#39;,
    			    contentType: &#39;application/json&#39;,
    			    url: url,
    			    dataType : &#39;jsonp&#39;,
    				success: function (result) {
    			
    			        result = jQuery.parseJSON(result);
    			        
    			        if(!result.data.email){
    			        	throw (&#39;New exception&#39;);
    			        }
    			        console.log(result);
    			        jQuery(&#39;.email&#39;).html(result.data.email);
    			    }
    			});
    		
    		
    			jQuery(&#39;.surveryButton&#39;).click(function(){
    				window.location.replace(&quot;http://&quot; + pgInventory.host + pgInventory.path + leadInfo[0] + &quot;&amp;curLeadId=&quot; + leadInfo[1] + &quot;&amp;curViewedPages=0&quot;);
    			});
    		}
    		catch(err) {
    			jQuery(&#39;.email&#39;).html(&#39;your e-mail address&#39;);
    			jQuery(&#39;#arrowContent&#39;).remove();
    		}
    });

Content Type	Original Author	Original Content on Stackoverflow
Question	JohnB	View Question on Stackoverflow
Solution 1 - Design Patterns	Blaise	View Answer on Stackoverflow
Solution 2 - Design Patterns	JMan	View Answer on Stackoverflow
Solution 3 - Design Patterns	Alex D	View Answer on Stackoverflow

Design patterns: exception / error handling

Design Patterns Problem Overview

Design Patterns Solutions

Solution 1 - Design Patterns

Solution 2 - Design Patterns

Solution 3 - Design Patterns

Passing data between different controller action methods

mysqlworkbench giving version error on exporting database

Attributions